Modern sports stadiums are costly to build and maintain. Hence it is in the owner's interest to use it as much as possible in order to meet the costs. For instance, the home ground of a football team is used for sports typically once every second week during the season, and even less outside the season. In addition there will typically be some other matches such as cup matches. As a result, the stadium will be left unused in most of its time. In the last decades, one has started to use such stadiums also for cultural events such as large concerts. Such events constitute an important income for the stadium owners.
However, a large concert held on a natural turf field will or may destroy the grass. Means of protecting the turf are often used, but are not always sufficient. Moreover such protecting means takes time to install and remove. As a result, the stadium owner cannot quickly change the modus of the stadium between a sports event and a cultural event. He is bound by his obligation to provide a quality turf for the sports event, making it difficult to provide possible dates for other cultural events.
This problem has existed for decades and several known solutions have been suggested to overcome it. Some solutions regard protecting or covering the field, while others involve removing the field instead of protecting it in situ.
German publication DE2924904 from 1980 describes a floor consisting of floor modules which are adapted to cover an ice field. The modules are plates that are removed from the ice and stored below a ceiling. Thus the modules protect the ice when the ice field is not in use.
Another system adapted for protection of an existing field is described in European patent application publication EP1500416. It describes a sheet cover rolled onto a roller that is arranged in a trench. To protect the turf field, the cover is rolled out and laid onto the field.
Turfgrass Bulletin presents an article in its October issue of 2001 (Issue No. 214) describing a pitch made up of movable turf modules. The modules are approximately 1-2 m2 each and are moved out of the stadium by an ordinary forklift. Below the turf modules there is a fixed support base, such as a concrete floor.
Such a system is also described in publication GB2138690. The publication describes how the individual modules can be moved or replaced to facilitate uneven wear or the turves to be equated from within the arena or replacement from spare units.
The solutions involving covering the turf field exhibit a problem in that the grass will deteriorate if covered for long periods. Furthermore, even if covered with plates or a sheet cover, events such as a concert, with all the associated equipment such as a stage and trucks and camera/sound gear and audience, will physically damage the turf.
The solutions involving removing the turf exhibit a disadvantage in that removing the vast number of turf modules is cumbersome and time consuming. Moreover, storage space for the turf modules is needed either outside the stadium or within the stadium construction. The latter represents valuable space such as for office premises, shops, VIP-rooms, etc. Hence this is not a desired solution.
The object of the present invention is to provide a solution that remedies the disadvantages of the solutions according to the prior art. A particular object of the invention is to provide a solution that makes possible a quick removal of the turf field and also a quick re-assembly of the turf field.